The International Astronomical Union — the organization
responsible for naming celestial objects — has approved
"Kerberos" and "Styx" as the new monikers for two of Pluto's moons
that were previously called P4 and P5 respectively, but fans of
TV's "Star Trek" might not be too happy about the new names.

The IAU selected the names based on the results of the Pluto
Rocks Internet poll sponsored by SETI (the Search for
Extraterrestrial Intelligence), but the top vote-getter, Vulcan,
ultimately wasn't chosen as a name for one of the tiny moons.
[ Photos
of Pluto and its Moons ]

Actor William Shatner — who portrayed the Starship Enterprise
captain James T. Kirk in the original "Star Trek" TV series —
suggested Vulcan (the home planet of the show's pointy-eared
Vulcan people) as a possible candidate, and voters overwhelmingly
cast their ballots in favor of it.

In total, nearly 500,000 votes were cast, with about 170,000 of
those going to Vulcan alone. In second place was Cerberus with
Styx coming in third in the online poll. But for Vulcan, it was
not meant to be.

"The IAU gave serious consideration to this name, which happens
to be shared by the Roman god of volcanoes," SETI officials wrote
in a statement. "However, because that name has already been used
in astronomy, and because the Roman god is not closely associated
with Pluto, this proposal was rejected."

IAU rules states that Pluto's moons should be named for
mythological characters of the underworld in Greek and Roman
mythology. Pluto is known as the ruler of the underworld in
ancient mythos.

Cerberus, the three-headed dog in Roman mythology, came in a
clear second in the Pluto
Rocks ballot with nearly 100,000 votes, but IAU officials
decided to tweak the name slightly, instead opting to name the
moon Kerberos — Cerberus' equivalent in Greek myth.

The name Styx, the river that separates the living from the dead
in ancient myth, garnered about 88,000 votes for a third place
finish.

Scientists used the Hubble Space Telescope to discover Styx
around Pluto in 2012. The space telescope also helped researchers
discover the existence of Kerberos in 2011. Both moons are about
15 to 20 miles (20 to 30 kilometers) in diameter.

In all, five moons are known to be orbiting Pluto. Charon, the
largest moon, was first spotted in 1978. Two more moons, Nix and
Hydra, were discovered by Hubble in 2005.

Scientists will get a close-up view of the two new moons and the
rest of the Pluto system in 2015 when NASA's New Horizons
spacecraft flies by. Bound for Pluto, the probe, launched in
2007, will search for additional moons that Hubble is unable to
detect and travel to the Kuiper Belt, a mass of icy bodies left
over from the early formation of the solar system.

Editor's Note: This story was updated at
12:25 p.m. EDT (1625 GMT) to correct an error. NASA's New
Horizons spacecraft was launched in 2006 and will fly by the
Pluto system in 2015.